Isolation of an L-Fucose Binding Protein from Lotus tetragonolobus Seed

Abstract

Morgan and Watkins¹ have shown that haemagglutination of group O human red blood cells by an aqueous extract of Lotus tetragonolobus seed is inhibited by L-fucose but not by D-fucose. In this communication we describe the isolation from L. tetragonolobus of a protein which binds specifically L-fucose and which agglutinates group O human red blood cells. The isolation is based on specific precipitation of the L-fucose binding protein by a dye containing three α-L-fucopyranosyl residues. The tri-functional fucosyl dye (l,3,5-tri-(p-α-L-fucosyloxyphenyl-azo)2,4,6-trihydroxybenzene) was prepared from p-amino-phenyl α-L-fucopyranoside² by diazotization and coupling to phloroglucinol in a manner similar to some other trifunctional glucosyl dyes³. The isolated protein is characterized in terms of its molecular weight and its L-fucose binding isotherm.